It has been found that the imposition of darkness by blindfolding brings about a highly significant decrease in the rate of human parotid gland function. The increases in potassium and chloride levels in saliva associated with this light-induced decrease in glandular function are the same as those noted in atropine-induced decreased rate of flow. Sodium concentration remained constant in each situation. This observation reinforces our premise that photic stimulation of retinal receptors is responsible for a component of sympathetic neuronal activity that plays a part in normal unstimulated secretion from the human parotid and that it may be the principal stimulus for resting secretion. Other portions of this work have involved the management of fluoride by the human salivary glands and the salivary response to exogenous fluoride. Studies have also involved glandular management of IgA and the possible correlation between salivary IgA and the degree of periodontal involvement.